DESCRIPTION: Pediatric constipation and encopresis typically develop in infancy or the toddler years and are treated by Primary Care Physicians (PCPs). This condition can be relatively treatment resistant and can culminate in devastating psychosocial consequences if it persists into school years. However, treatment literature of this condition typically involves older children (6 or more years of age), who have an extensive history of treatment failure, have associated behavioral problems, and are treated at specialty clinics. Consequently, available studies bear an unknown relationship to routine clinical care by PCPs of young children. Additionally, there are little developmental data on this symptom pattern. Building on the investigator's current research with children 6-15 years, a descriptive study to evaluate the mechanisms of constipation and encopresis in early childhood (ages 2-6), and treatment efficacy by PCPs is proposed. This study will evaluate patients immediately before and two months following routine care by their PCP. This evaluation will include physical, psychological and behavioral variables to test a proposed bio-psycho-behavioral model of constipation-encopresis. Patients who do not respond to this initial intervention will then enter an experimental study, and be randomly assigned to either continued care by their PCP or referred to a specialty clinic where they will receive intensive laxative therapy or intensive laxative therapy plus behavior therapy (enhanced toilet training). This latter 3 (pre-post-12 month follow up) x 3 (treatment groups) study will allow a test of a model concerning the development, maintenance and treatment- responsiveness of early childhood constipation and encopresis, as well as allow an assessment with the relative cost-effectiveness of these three modes of treatment. Not only will this research represent the first prospective description and evaluation of PCP routine care, but it also represents the first experimental treatment outcome study of early childhood constipation encopresis.